














COPYRIGHT DEPOSIT 


































































































































































































THE LIGHT 
OF 

THE WORLD 

COMPILED BY WORKERS OF THE 
WRITERS’ PROGRAM OF THE WORK 
PROJECTS ADMINISTRATION IN THE 
COMMONWEALTH OF PENNSYLVANIA 


—JUNIOR PRESS BOO KS- 

ALB ERTXWHITMAN 

&" 4 co 

CHICAGO 1940 





PENNSYLVANIA DEPARTMENT OF PUBLIC INSTRUCTION 
State-wide Sponsor of the 
Pennsylvania Writers' Project 


FEDERAL WORKS AGENCY 
John M. Carmody, Administrator 

WORK PROJECTS ADMINISTRATION 

F. C. Harrington, Commissioner 
Florence Kerr, Assistant Commissioner 
Philip Mathews, State Administrator 


COPYRIGHT DEPOSIT. 

RECEIVED 

OCT -5 1940 

COPYRIGHT OFFICE 

Co-sponsored and copyrighted, 1940, by Division of Extension Education 
Board of Public Education, Philadelphia. 


FOREWORD 


The Light of the World is the twelfth of thirty 
booklets in the Children's Science Series. It 
was prepared by the Philadelphia Unit of the 
Pennsylvania Writers' Project, sponsored by 
the Pennsylvania Department of Public In¬ 
struction. 

This booklet, written by Mark Bartman, was 
edited by Katharine Britton of the State office 
staff. 

Acknowledgment is made to Wagner Schles- 
inger, Associate Director in charge of Astron¬ 
omy, Franklin Institute, Philadelphia, for act¬ 
ing as consultant to assure accuracy of the text 
and illustrations. 

Illustrations were prepared by workers of the 
Pennsylvania Art Project, under the direction of 
Michael Gallegher, who also executed the 
jacket design. Inside illustrations are the 
work of David Cain, Bryan Pringle, and 
Mary Procopio. 

C. C. Lesley 
State Supervisor 



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THE LIGHT OF THE WORLD 


Once upon a time, so an old story says, 
the wind and the sun had a quarrel. 
Each one boasted that he was more 
powerful than the other. The quarrel 
became so bitter that they felt they must 
settle it by a test of strength. 

On the earth far below, they saw a 
man walking, his coat buttoned about 
his neck. "Look,” said the wind, "the 
one that can make that man down there 
take off his coat first is the stronger!” 
And with a great howl, he swept down 
upon the traveler, blowing a blast that 
was fierce and strong and cold. He tore 


6 CHILDREN’S SCIENCE SERIES 

at the traveler’s coat with stinging 
fingers. But the traveler shivered and 
clutched it closer. Harder and harder 
puffed the wind. Louder and louder he 
howled. But the traveler only bent his 
head and hugged his coat more tightly. 

Then the sun brushed the wind aside 
and shone down upon the earth with 
all his power. The air grew warmer 
and warmer, the clouds melted away. 
Soon the traveler opened his coat. As 
the heat kept pouring down, wheat stalks 
in the fields drooped their heads, leaves 
shriveled, and ponds dried up. The 
traveler tore off his coat and flung him¬ 
self under a shady tree. Now the victori¬ 
ous sun dropped behind the hills, and 
the earth became cool and pleasant. 
Then the wind knew he was beaten, and 
fled away to hide in the cracks of a 
mountain cave. 


THE LIGHT OF THE WORLD 


7 


WHAT DOES THE SUN DO FOR US? 

This is not a true story, of course, but 
it shows the great power of the sun. 
Though we may not think much about 
it, the sun is the most important thing 
in our lives. If it were taken away, the 
earth would have no light or heat. 
Everything would be black, darker than 
any darkness we know. Soon the 
whole earth would be covered with a 
heavy crust of ice and snow. 

Every flower, fish, bird, and animal 
would freeze and die. For living things 
must get heat and strength from the sun 
if they are to live and to grow. Plants 
drink in the heat of the sun and store it 
as energy inside their leaves and stems 
and roots. Then when people or animals 
eat the plants, they take that energy 
and strength into their own bodies. 

Even the heat in the coal men bum is 
heat from the sun. For coal is made of 


8 CHILDREN'S SCIENCE SERIES 

the leaves and stalks of giant plants 
that grew in the sunlight upon the earth 
long, long ago. These plants died and 
were buried under rock and then pressed 
into the hard black coal that is used 
today. Coal has a great deal of stored 
heat. But if all the coal in the world 
could be burned at once, it would not 
give us so much heat as the sun does. 

Certainly if there were no sun every¬ 
thing on earth would be completely 
different from what it is today. 

HOW BIG IS THE SUN? 

We may think there is nothing in the 
heavens at all like our sun. But there 
are other suns, billions of suns, and 
some of them are many times bigger 
than our own. The earth does not get 
much light or heat from these other suns 
because all of them are so far away that 
they are seen only as pinpoints of light 
at night. Yes, they are the stars! Our 


THE LIGHT OF THE WORLD 


9 



ALL THESE FOODS COME FROM LIVING THINGS THAT GREW IN 
THE SUNSHINE. THE SUN’S HEAT IS STORED UP IN THEM 

AS ENERGY. 

sun and the stars are brothers. All of 
them are great, hot, glowing bodies, float¬ 
ing through space. 

But none of the stars is so important 
to the earth as the sun. The earth is 































































10 CHILDREN’S SCIENCE SERIES 

much nearer to the sun than to other 
stars. It moves with the sun through 
the heavens. It is part of the sun’s 
family. 

Because the sun is nearer than other 
stars, it seems larger to us. Still, it 
does not appear very large. We can 
find out how small it seems by trying 
a little trick. Let us ask a friend to 
stand six feet away from us and hold 
up a dime between our eyes and the sun. 
When our friend holds the dime in the 
right position, it covers the whole face 
of the sun. So if we believe our eyes, 
we must think the sun is as large as a 
dime. Can something as large as a dime 
give out enough heat and light to keep 
the whole earth bright and warm? 

The answer is that we must not believe 
our eyes. The sun is very much larger 
than it seems. There are men who spend 
a great deal of time studying the sun 
and the stars. These men, called astron- 


THE LIGHT OF THE WORLD 11 

omers, have found the sun’s real size by 
very careful measuring. They say that 
the distance straight through the sun, 
from one side to the other, is 864,000 
miles! It would take 108 balls as big as 
the earth, placed side by side, to stretch 
that far. 

Suppose we think of the sun as the 
size of a large pumpkin. The earth be¬ 
side it is now only the size of a very small 
pea, so small that it is scarcely seen 
beside the big pumpkin. About one 
and one-third million balls the size of 
the earth would have to be pressed to¬ 
gether to make one ball as big as the 
sun. The sun may not be so large as 
some stars, but it is still a giant. No 
wonder it is able to shed so much light 
and heat upon the earth. 

HOW FAR AWAY IS THE SUN? 

We can see only the outside, or surface, 
of the sun. Yet this surface alone is so 


12 CHILDREN’S SCIENCE SERIES 

bright that we cannot look at it without 
blinking our eyes. Of course, a very 
strong electric bulb can make us blink 
too. But the bulb is close to our eyes. 
Its light does not have to travel far. 
We can realize how strong the light of 
the sun must be when we think that it 
must travel to the earth through ninety- 
three million miles of space. 

Ninety-three million miles! That’s as 
far as going around the world about 
3,720 times. It makes our heads swim. 
If an explosion took place on the sun 
and the sound could travel to earth, it 
would not be heard here until 15 years 
after the explosion had happened! 

Just suppose it were possible for an 
automobile to travel to the sun. Sup¬ 
pose the automobile traveled night and 
day without stopping, at 50 miles an 
hour. It would take 210 years to reach 
the sun. 


THE LIGHT OF THE WORLD 


13 



WHY DOES THE SUN SHINE? 

Of course, no automobile could travel 
to the sun. But if it could, it would 
melt. For the sun is hotter than we 
can possibly imagine. It is hotter than 
the hottest fire that could be made here 
on earth, hotter than the furnaces in 
which iron and gold and other metals are 
melted. We are lucky that we do not 
come close to the sun, and that it does 



14 CHILDREN’S SCIENCE SERIES 

not come close to us. If it did, it would 
burn up the earth. 

The sun itself is not burning, however. 
If it were burning like an ordinary fire, 
it would burn to dust and ashes in 1,500 
years. But it has been giving off heat 
and light for millions of years, and it will 
go on doing so for many more millions 
of years. 

It may seem strange that the sun is 
so bright if it is not burning. Some 
people think things have to burn to give 
light. But, let’s look at an electric bulb. 
We press a button, and the light flashes 
on. Yet the bulb is not burning. What 
happens is that the wire in the bulb 
gets so hot that it shines brightly. The 
sun shines for the same reason. The 
materials of which it is made are so hot 
that they glow. 

If heat makes the materials of the sun 
shine, it must do something else to them 
too. Even though they are not burning, 
certainly in that terrible heat they can- 


THE LIGHT OF THE WORLD 15 

not be the same as they would be if they 
were cold. All of us have seen some of 
the changes that heat can make in 
things. Butter, or even iron, melts if it 
gets hot enough. When water is heated 
enough, it turns to steam, or gas. These 
changes take place in all things, even the 
hardest stone or metal, if they become 
hot enough. At a certain point, they 
melt. And if they are heated more and 
more, they will at last turn to gas. 

Some things, of course, need much less 
heat than others in order to melt or turn 
to gas. Ice and snow, for instance, melt 
while they are very cold. Our earth is 
not hot enough to melt most things. If 
it did become hot enough, even our tall 
stone buildings would melt like ice cas¬ 
tles. But of course it is not possible for 
the earth to become so hot. 

The sun, however, has enough heat to 
turn to gas all the materials of which it 
is made. And that is exactly what has 
happened. Although the sun has iron, 


16 CHILDREN’S SCIENCE SERIES 

nickel, copper, tin, oxygen, and probably 
all the other materials that the earth 
has, these materials are much different 
there. On earth most of them are solid. 
On the sun all of them are gases, each 
shining brightly. 

HOW MUCH HEAT DOES THE SUN GIVE 
US? 

All of us have seen pictures of tne sun 
with rays shooting out like spokes from 
the center of a wheel. The sun does not 
really look like this, of course, but the 
pictures want to show how the light and 
heat pour from the sun in all directions 
through space. Only a few of those rays 
travel in the direction of the earth. But 
suppose all the sun’s rays could be turned 
in our direction. There would be enough 
heat to melt in one second a bridge of 
ice two and one-half miles thick reach¬ 
ing all the way from the sun to the 
earth. 

Some of the heat that does flow toward 


THE LIGHT OF THE WORLD 17 

us does not reach the earth’s surface. 
For there is a blanket of air stretching 
for many miles all around the earth. 
This is the air we breathe. This air 
keeps some of the sun’s heat for itself, 
and turns some of it back into space. 

So only a small part of all the sun’s 
heat ever reaches us. Yet even that 
small part is a great deal. The earth 
does not seem to be getting much heat 
on a winter day when we shiver in 
woolen clothes. But if the heat of all 
our winter days were added together, the 
total would surprise us. In one year 
we get enough heat to melt a crust of ice 
114 feet thick, covering all the world. 
If one half of the earth were turned to 
the sun all the time, that half would be 
baked hard as brick. The other side 
would be cold and dark. 

Luckily that does not happen. Every 
part of the earth has both day and night. 
Every part gets heat and light from the 
sun regularly. 


18 


CHILDREN’S SCIENCE SERIES 



THE HALF OF THE EARTH ON WHICH THE SUN SHINES IS 
BRIGHT. THE OTHER HALF IS IN DARKNESS. 

NIGHT AND DAY 

If we get up very early some morning, 
we can see the sun come up over the 
fields or hills or houses in the eastern 
part of the sky. At night it goes down 
below the land in the west. It seems to 
travel right across the sky. 

People long ago used to think that the 
sun really did move overhead like this 
every day. And they believed that the 



THE LIGHT OF THE WORLD 19 

earth was flat. After a while, they found 
out that the earth was round, much like 
a ball. Then they thought that the sun 
went around the earth, taking twenty- 
four hours to make the trip. 

Today people know that the sun is not 
moving around the earth. It is the earth 
that is turning. Sometimes when we 
ride on a train the trees outside seem to 
be skimming quickly past us. But we 
know that it is really the train that is 
rushing past the trees. And we know 
too that though the sun seems to be 
moving, it is really the earth that is 
tinning. 

Our earth is spinning like a top. It 
takes about twenty-four hours to make 
one turn, and that is one whole day. 
Because of this turning, all parts of the 
earth have both darkness and light. The 
parts that the sun’s rays reach are bright. 
Those parts turned away from the sun 
are in shadow or darkness. 



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22 CHILDREN’S SCIENCE SERIES 


But every part of the earth does not 
have just the same amount of darkness 
and of light every day. Only at the 
middle of the earth, called the Equator, 
does this happen. There the night is 
always twelve hours long, and the day 
is the same. 

In other parts of the earth, the hours 
of daytime and nighttime change from 
day to day. In winter, nights are long 
and days are short. In summer, the 
sun goes down so late that we have to 
go to bed sometimes while it is still light. 
And if we lived at the North Pole, the 
sun would be shining all summer, even 
while we slept! For there darkness does 
not come every day as it does here. 
There is only one night, and it lasts for 
months, all during our autumn and 
winter. Then the sun comes up over 
the snow-covered land, and it can be 
seen at all hours during our summer and 
spring. At the South Pole, it is the 
other way around. The sun is shining 


THE LIGHT OF THE WORLD 23 

down there while the trees in our coun¬ 
try are bare and the ground is covered 
with snow. 

All these differences in day and night 
happen because the sun is shining on 
the earth differently at different times 
of the year. Dinring our spring and 
summer, the northern half of the earth 
is tilted more toward the sun. So it 
receives the sun’s rays for a longer time 
each day. During our autumn and 
winter, the southern half of the earth 
is tilted toward the sun, and receives 
the sun’s rays for a longer time each day. 

TELLING THE TIME 
People learned a very long time ago 
that they could tell time by the sun. 
They learned where the sun would be 
in the sky on each day, and at each 
hour of the day. Then they could squint 
up at the sky, with hand shielding their 
eyes, and judge the time. After a while 
they made something which helped them 


24 CHILDREN’S SCIENCE SERIES 

to measure the position of the sun, and 
so tell time more exactly. This was a 
sundial. Sundials were first used more 
than 2500 years ago. 

One of the best types of sundials had 
two parts. It had a round face, or dial, 
which looked straight up to the sky. 
Set on the face, in the same way we hold 
a pencil on a paper to write, was a strip 
of metal, stone, or wood. This pointed, 
like a finger, directly to the north. 

The face of the sundial was first di¬ 
vided into quarters, by a line running 
east and west, and one running north 
and south. Then each quarter was 
marked by hour spaces. The strip of 
metal cast a shadow on the dial, and 
the edge of the shadow marked the hour. 
As the sun moved across the sky, the 
shadow moved around the face of the 
dial. 

The main trouble with the sundial 
was that it could not be used during 



SUNDIALS LIKE THIS ONE CAN STILL BE SEEN SOMETIMES 
IN PARKS AND GARDENS. 


























26 CHILDREN’S SCIENCE SERIES 


the night or during cloudy weather. 
Also, it was not correct at all times 
and for all places on the earth. Several 
hundred years ago clocks came into use. 
Today sundials are no longer used to 
tell time. But we can still see them 
sometimes, in parks or in gardens. 

THE SEASONS OF THE YEAR 

The earth’s time is divided not only 
into days, but also into years. Every 
365 days a new year begins on earth. 
Each year has a winter, a spring, a 
summer, an autumn. Even before we 
know exactly why this is, we can guess 
that the earth’s moving must have some¬ 
thing to do with it. And that is true. 
Let us see if we can find out how it 
happens. 

We know that the earth is turning 
like a top, and makes one whole turn 
every twenty-four hours. Well, the 
earth is moving in another way too. 



WHILE THE EARTH SPINS, IT ALSO TRAVELS IN ITS ORBIT 
AROUND THE SUN. AT THE SAME TIME, THE MOON TRAVELS 
IN AN ORBIT AROUND THE EARTH. 



28 CHILDREN’S SCIENCE SERIES 

While it spins, it also travels in a 
big circle around the sun. This circle 
is called the earth’s orbit. It takes the 
earth about 365 days to make one whole 
trip around the sun and come back to 
the place from which it started. So 
every 365 days the earth is in the same 
place in its orbit, and the sun is shin¬ 
ing on it the same way. 

When it was first suggested that the 
earth moved around the sun, people were 
frightened. At that time they still be¬ 
lieved that the sun traveled around the 
earth. They thought that it would make 
the earth less important if it traveled 
around the sun. It made them un¬ 
happy to hear that the earth was not 
the center of everything. So for a long 
time they refused to believe the truth. 
Today no one minds at all the idea that 
the earth is not the center of the heavens. 
Men are eager to find out all they can 
about its movements. 

From day to day as it moves in its or- 


THE LIGHT OF THE WORLD 29 

bit, the sun’s rays fall on different parts 
of the earth in different ways. At any 
particular time, some parts are facing 
the sun, and the sun’s rays are falling 
straight down on them. So they get a 
great deal of heat from the sun and they 
become very warm. At the same time, 
other parts of the earth are getting only 
low slanting rays. Those parts receive 
very much less heat, and they become 
cold. 

Every year about June 22, the sun’s 
rays are falling almost straight down on 
the northern half of the world, the half 
in which we live. Our summer begins 
at that time. Corn and grain begin to 
grow tall in the fields, and then they 
ripen in the hot sun, and are cut and 
gathered. Slowly the position of the 
world is changing, until the sun’s rays 
are reaching us at a slant. The wind 
grows colder, and whips the yellow leaves 
from the trees. Sadly we say that the 
sun is moving south. 


30 CHILDREN’S SCIENCE SERIES 

By December 22, the sun’s rays are 
coming to us at a very great slant. 
Even in the sunlight, the air is bitter 
cold. Our winter begins. Snow falls 
and frost draws beautiful pictures on 
the windows. For us, this is the time 
of snow battles and sleds. But now the 
sun’s rays are falling nearly straight 
down on the southern half of the world. 
And while we are having winter, flowers 
and fruits are blooming down there, and 
the sun is tanning people’s skins from 
white to brown. 

Each second of the day diming the 
summer we receive more heat from the 
sun than we do in the winter. But there 
is another thing which helps to make 
summer so hot and winter so cold. In 
summer we are receiving heat for a 
longer time each day. On the longest 
day, there are about fifteen hours of 
light and only nine hours of darkness. 
So we are receiving heat from the sun 
for fifteen hours, and we have only nine 


THE LIGHT OF THE WORLD 


31 


IN WINTER THE SUN'S 
RAYS REACH US AT A VERY 
GREAT SLANT. THIS IS THE 
TIME OF SNOW BATTLES. 



WHEN THE SUN’S RAYS ARE 
FALLING ALMOST STRAIGHT 
DOWN ON THE NORTHERN 
HALF OF THE WORLD, OUR 
SUMMER BEGINS. PLANTS 
GROW TALL AND RIPEN. 


hours in which to cool off. In the winter, 
however, darkness lasts for fifteen hours, 
and the earth grows very cold during 
the night. 














32 CHILDREN'S SCIENCE SERIES 

THE WORLD’S BIGGEST SHADOW 

Long ago people noticed that once in 
a great while the whole sun, or part 
of the sun, seemed to disappear, even 
on a clear day. Sometimes at night 
the moon seemed to become dim for a 
while. People were greatly frightened 
when they saw these things, and they 
tried to think of reasons to explain what 
happened. 

Many years ago the people of north¬ 
ern Europe believed that the sun and 
the moon were chased by two very large 
wolves. Once in a great while the wolves 
caught them, and ate part of them. 

The Chinese of long ago believed that 
there was a dragon which sometimes 
tried to swallow the sun. When the sun 
disappeared, they would rush out into 
the streets, beating gongs and making 
a great noise to frighten the dragon 
away. Then when the sun came out 


THE LIGHT OF THE WORLD 


33 



SOMETIMES THE MOON GETS RIGHT BETWEEN THE SUN AND 
THE EARTH, AND THE SUN IS HIDDEN FROM VIEW. 


again there was dancing and singing 
and feasting. 

Neither the Chinese nor the people of 
the North were right, of course. But 
we would not be far wrong if we said 
that the sun and the earth and moon 
play hide-and-seek with one another. 
Before we can understand their game, 
however, we must know several impor¬ 
tant things about the moon. 

The moon is a big ball, though it is 






34 CHILDREN’S SCIENCE SERIES 

much smaller than the earth. It circles 
around the earth in the same way that 
the earth circles around the sun. It has 
its orbit, or path, around the earth. As 
the earth moves around the sun, the 
moon moves with the earth. 

Sometimes, as the moon moves in its 
orbit, it gets right between the sun and 
the earth, and the sun is hidden from 
view. This is called an eclipse of the 
sun. It is as if someone had passed a 
saucer over the sun’s face. When the 
whole sun is hidden, there is a total 
eclipse. When the moon does not cover 
all of the sun’s face there is a partial 
eclipse. 

There can be an eclipse of the moon 
too. When that happens, the earth is 
right between the sun and the moon. 
So all of the sun’s light cannot reach the 
moon, and the moon fades and turns 
dull red. 

But eclipses do not happen very often. 


THE LIGHT OF THE WORLD 35 

In one year there are only from two to 
five eclipses of the sun in different parts 
of the world. There are at most three 
eclipses of the moon. Most of these are 
only partial eclipses, since part of the 
sun or the moon is not hidden. 

Even during a total eclipse of the sun, 
the shadow cast by the moon does not 
cover the whole earth, of course. Only 
a part of the earth is in shadow, while 
one small place is in darkness. But a 
total eclipse is not likely to be seen 
from any one spot more than once in 300 
years. Astronomers make long trips 
from distant parts of the earth to the 
place where a total eclipse will be seen 
best. 

If we watch a total eclipse of the sun 
through a pair of dark glasses, we see 
the round moon slowly covering the face 
of the sun. For a few minutes the earth 
becomes dark and stars come out. Birds 
stop singing, flowers close, cows start 



for home, chickens go to roost. Then 
the moon passes on and the sun shines 
again. 


36 CHILDREN’S SCIENCE SERIES 


TONGUES OF ROSE-COLORED LIGHT CAN BE SEEN AROUND 
THE MOON DURING AN ECLIPSE. 




THE LIGHT OF THE WORLD 


37 



WHEN THE SUN IS COMPLETELY HIDDEN DURING AN ECLIPSE, 
A CROWN OF PEARLY-WHITE LIGHT CALLED THE CORONA 
APPEARS. 


During the time when the sun is com¬ 
pletely covered, a great number of 
tongues of rose-colored light can be seen 
around the edge of the moon. And 
shooting out beyond these on all sides 
are great streamers of pearly-white light. 
This crown of pearly-white light is called 



38 CHILDREN’S SCIENCE SERIES 

the Corona. Waiting for the Corona to 
appear is the most exciting part of watch¬ 
ing an eclipse. 

By figuring very carefully and keeping 
records, astronomers can tell when an 
eclipse is going to happen, even to the 
exact moment. So it is easy to find 
out when the next eclipse can be seen 
from our homes. Then we must take 
care not to miss it, for a long time will 
pass before we can see another. 

SUNSPOTS 

Several hundred years ago an Italian 
astronomer named Galileo heard about 
an invention which made objects far 
away seem much bigger. This was a 
telescope, a long tube with special pieces 
of glass in it. Telescopes are something 
like field glasses, but very much larger. 
With the telescope it was possible to 
find out many new facts about the sun. 

Galileo said that the telescope showed 


39 


THE LIGHT OF THE WORLD 

spots on the sun’s face. But people did 
not believe this. They thought Galileo 
was crazy. They said that he was in¬ 
sulting the sun by saying that it was 
not perfect. 

Later studies, however, have showed 
that Galileo was right. There really 
are spots on the sun. They are patches 
not so hot as the rest of the sun’s 
surface, so they look less bright. Most 
of them are too small to be seen from 
the earth without a telescope. Yet they 
are really from one thousand to several 
hundred thousand miles across. 

With a camera and a telescope, as¬ 
tronomers can take special pictures of 
the sunspots. These pictures show that 
the spots are giant eddies, or whirlpools, 
in the sun’s surface. They look some¬ 
what like water whirling below a water¬ 
fall. If we look at a picture of a 
tornado, or windstorm, we can get a very 
good idea of what the sunspots are like. 


40 CHILDREN’S SCIENCE SERIES 


They are simply pools of gases in 
the sun’s surface, whirling just like the 
wind and clouds in a tornado. 

As astronomers watched the sunspots 
through their telescopes, they saw that 
all the spots were moving. Every day 
each spot would be moving nearer to 
one edge of the sun’s face. Finally it 
would disappear over the edge. Then 
after a number of days had passed, it 
might be seen again on the other edge. 
Suddenly someone saw the reason for 
this. The sun must be turning like a 
top, just like the earth. So astronomers 
counted the days that it took a sunspot 
to travel around and come back to the 
same place. They found that the sun 
made one whole turn in about 27 earth 
days. 

Sometimes there are no sunspots. 
Sometimes the sun’s face is full of them. 
It has been found that they appear in 
greatest numbers about every eleven 



THE ELECTRIC WAVES REACHING THE EARTH FROM 
SUNSPOTS INTERFERE WITH OUR ELECTRIC WAVES. 



42 CHILDREN’S SCIENCE SERIES 

years. Then there may be 50 to 100 
seen at one time. No one knows why 
this happens. But astronomers have 
noticed that the number of sunspots 
seems to affect other things, both on the 
sun and on the earth. 

For instance, the shape of the Corona 
seen during an eclipse depends upon the 
number of sunspots. When there are a 
great many sunspots, the Corona is 
round. At other times it is longer and 
narrower. 

But the number of sunspots has an¬ 
other effect, which is more important 
to the people on earth. The huge pools 
of whirling gases that make the spots 
are full of electricity. Waves of elec¬ 
tricity are pouring down upon the earth 
from any spots that are turned in our 
direction. These electric waves do 
strange things to the electricity made 
by men. They cause electric storms 
here on earth, and these electric storms 


THE LIGHT OF THE WORLD 43 

do as much damage as heavy rainstorms 
can do to trees and flowers. They inter¬ 
fere with the radio and the telephone. 
They mix words and letters so that mes¬ 
sages sent by telegraph are destroyed. 

The sunspots also affect the electric 
waves which cause the Northern Lights, 
those bright white and colored lights 
that we sometimes see in our northern 
sky. When there are many sunspots, 
the Northern Lights become very much 
brighter and more beautiful. 

Some men think that when the num¬ 
ber of sunspots is great, there are also 
more of those sun rays that make vita¬ 
mins and build health. But this has 
not yet been proved. 

There are other ideas, too, about the 
action of the sunspots. Some men say 
that they cause war or peace, and bring 
wealth or poverty to nations. Others 
say that people’s feelings, thoughts, and 
health are changed by the sunspots. 


44 CHILDREN’S SCIENCE SERIES 

However, from what we know of the 
sunspots today, there is no reason to 
think that these people are right. The 
sunspots are still a mystery. 

SUN WORSHIP 

Since the sun was so important to 
men, and at the same time was such a 
mystery to them, it is not surprising 
that there have been many people who 
believed that the sun was a god and 
worshiped it. It gave them warmth 
and growth and strength. It seemed to 
give them even life itself. 

The early Egyptians prayed to the sun. 
The Greeks had a sun god, the beautiful 
Apollo. The Japanese still use the sign 
of the sun on their flag. They call their 
country the Land of the Rising Sun, 
and claim that their ruler is descended 
from the sun. 

The Indians of the western United 
States were also among those who 


THE LIGHT OF THE WORLD 45 

thought the sun was a god. Every year 
about the time of the harvest they held 
a sun dance. Each tribe of Indians had 
its special reason for the dance. Some¬ 
times they wanted to ask for help. But 
often they just wanted to thank the sun 
for the good things it gave them. 

The sun dance celebrations lasted 
eight days. The members of the tribe 
arranged their tepees, or tents, around 
the big tepee of the medicine man, leav¬ 
ing an open space facing the rising sun. 
The Indians, with bodies painted in 
many colors, danced around a decorated 
pole in the center. 

Today the sun dance is still performed 
among some Indians of the West, and 
many people go there to see it. But it 
has been greatly changed. Our Gov¬ 
ernment does not permit it in its old 
form because of the tortures that took 
place during the celebration. 

Of course, we know today that the sun 


46 CHILDREN'S SCIENCE SERIES 

is not a god. But we can agree with 
the people of long ago that it is the 
source of many good things. Even 
though it is not worshiped any longer, 
the sun still gives us light and heat and 
strength and health. 
















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